SANDIA LAB NEWS

July
8
,
2005

Materials
used
for
NASA’s
future
planetary
exploration
missions
are
being
put
to
the
test
at
Sandia
—
severe
heating
tests
that
is.

For
the
last
two
years,
tests
have
been
conducted
at
Sandia’s
National
Solar
Thermal
Test
Facility
to
see
how
material
can
withstand
severe
radiant
heating.
The
tests
apply
heat
equivalent
to
1,500
suns
to
spacecraft
shields
called
Advanced
Charring
Ablators.
The
ablators
protect
spacecraft
entering
planetary
atmospheres
with
significant
radiation
environments.

Under
a
Work
for
Others
Agreement,
researchers
at
Sandia
and
Applied
Research
Associates,
Inc.
are
conducting
the
tests
for
NASA
Marshall’s
In-Space
Propulsion/Aerocapture
Program.
The
R&D
effort
is
tied
to
NASA’s
plan
for
a
future
Titan
mission
with
an
orbiter
and
lander.
Titan
is
Saturn’s
largest
moon.

The
tests
are
led
by
Solar
Tower
expert
Cheryl
Ghanbari
(6218)
and
Bill
Congdon,
project
principal
investigator,
for
Applied
Research
Associates,
Inc.
The
tests
are
designed
to
simulate
atmospheric
heating
of
spacecraft
that
enter
Titan
—
heating
that
includes
low
levels
of
convective
heating
combined
with
relatively
high
levels
of
thermal
radiation.

The
primary
ablator
material
for
the
Titan
mission
will
be
low-density
silicones
and
phenolics,
all
under
20
pounds
per
cubic
foot
density.

To
date,
more
than
100
five-inch-diameter
cylindrical
samples
have
been
tested
to
the
solar
environment
inside
the
tower’s
wind
tunnel
using
a
large
quartz
window.
Congdon
says
because
of
Titan’s
relatively
high
radiation
environment,
some
initial
concerns
had
to
be
put
to
rest
through
testing.
He
said
radiation
might
penetrate
in-depth
within
the
ablator,
causing
an
increased
“apparent”
thermal
conductivity
and
degrading
insulation
performance.

“Radiation
could
also
generate
high-pressure
gasses
within
the
ablator
leading
to
spallation,”
Congdon
says.

“We
have
been
testing
at
Solar
Tower
to
see
how
the
candidate
Titan
materials
can
withstand
the
expected
range
of
heating
conditions,”
Cheryl
says.
“Titan
has
a
nitrogen-rich
atmosphere
and
nitrogen
is
used
in
tests
to
similarly
reduce
ablator
oxidation
while
energy
from
the
sun-tracking
heliostats
is
focused
on
the
samples.”

Congdon
says
ground
tests
are
necessary
to
understand
and
model
surface
ablation
of
the
materials
that
will
be
severely
heated
during
Titan
entry.
During
thermal
radiation
testing
conducted
in
the
Solar
Tower
all
of
these
concerns
were
addressed
and
found
not
to
be
a
problem
for
the
ablators.

Shots
of
heat

The
Solar
Tower
consists
of
an
eight-acre
field
of
220
solar-collection
heliostats
and
a
200-foot-
tall
tower
that
receives
the
collected
energy
at
one
of
several
test
bays.
A
single
heliostat
contains
25
mirrors
that
are
each
four
feet
square.
Total
collection
area
of
220
heliostats
is
88,000-square
feet.
Since
the
heliostats
are
individually
computer
controlled,
test
radiation
can
be
a
shaped
pulse
as
well
as
a
square
wave
in
terms
of
intensity
vs.
time.

Test
samples
are
mounted
high
in
the
receiver
tower,
and
the
heliostats
direct
the
sunlight
upward
to
irradiate
the
sample
surface.
The
samples
are
mounted
in
a
water-cooled
copper
plate
inside
the
wind
tunnel
with
a
quartz
window
that
allows
entry
of
the
reflected
radiation.
Exposure
is
controlled
by
a
fast-moving
shutter
and
by
pre-programmed
heliostat
movement.
Radiation
flux
is
calibrated
before
and
after
each
test
by
a
radiometer
installed
to
occupy
the
same
position
as
the
test
sample.
Cooling
effects
from
imposed
surface
flows
are
calibrated
via
a
flat-plate
slug
calorimeter.

The
materials
are
subject
to
square
pulse
environments
at
flux
levels
of
100
and
150
W/cm2
for
time
periods
that
far
exceed
predicted
flight
durations
for
such
high
heating.
They
are
also
subjected
to
“exact”
flux
vs.
time
environments
(simulating
actual
flight
conditions)
using
programmed
heliostat
focusing
at
the
Solar

Tower
facility.

The
material
samples
are
installed
in
the
Tower’s
wind
tunnel
and
exposed
to
the
solar
beam
at
flux
levels
up
to
150
W/cm2,
which
is
approximately
1,500
times
the
intensity
of
the
sun
on
earth
on
a
clear
day.
During
the
exposure,
air
blows
past
the
sample
at
about
mach
0.3,
and
below
this,
the
sample
is
immersed
in
a
high-speed
nitrogen
layer.

Cheryl
says
tests
can
be
conducted
only
during
about
four
hours
midday
bracketing
solar
noon.
Haze,
clouds,
and
high
winds
that
affect
the
heliostats
can
degrade
test
conditions.

Current
results

“All
of
the
candidate
materials
showed
no
spallation
and
very
good
thermal
performance
to
these
imposed
environments,”
Congdon
says.
Recently,
five
12-inch
by
12-inch
panel
samples
were
tested
on
top
of
the
tower.
Up
to
20
additional
12-inch
panels
will
be
tested
late
in
the
summer
followed
by
testing
of
2-foot
by
2-foot
panels
later
in
the
year.

Additional
tests
for
convective
heating
have
been
conducted
on
identical
material
samples
at
the
Interaction
Heating
Facility
(IHF)
at
NASA’s
Ames
Research
Center.
--
Michael
Padilla

Sandia
has
purchased
a
4,096-node
Dell
high-performance
computer
cluster,
called
Thunderbird,
that
will
provide
more
than
8,000
processors
of
compute
capacity
to
meet
the
laboratory’s
high
demand
for
cluster
computing.
The
aggregated
capacity
of
the
computer
will
have
approximately
24
terabytes
memory
and
60
tera-OPS
(trillion
operations
per
second)
speed.

Sandia,
with
Dell
Professional
Services
and
Albuquerque’s
Technology
Integration
Group,
will
install
the
system
at
Sandia’s
Central
Computing
Facility
in
Albuquerque.
Delivery
of
Thunderbird
should
be
completed
by
the
end
of
July
and
integration
and
testing
will
occur
over
the
next
several
months.
The
system
is
expected
to
be
fully
operational
in
early
October.

Thunderbird
is
Sandia’s
second
installment
of
an
institutionally
maintained
cluster.
Sandia’s
first
institutional
cluster
was
installed
October
2003
and
provides
approximately
seven
tera-OPS
of
capacity
to
the
laboratory.

“Our
first
institutional
cluster
was
an
important
investment
for
the
lab,
but
it
has
been
fully
utilized
from
the
first
day
it
was
installed,”
says
Ken
Washington,
CIO
and
director
of
Sandia’s
Information
Systems
and
Services
Program.
“Thunderbird
will
make
a
huge
impact
by
more
than
quadrupling
our
institutional
capacity.
The
increase
allows
the
Labs
to
meet
a
significant
fraction
of
previously
unmet
institutional
capacity
computing
requirements
in
one
fell
swoop.”

Thunderbird
is
referred
to
as
a
capacity
cluster
because
it
is
ideally
suited
to
perform
many
mid-sized
tasks
with
extreme
rapidity,
rather
than
one
huge
task
across
its
entire
system
like
Sandia’s
highly
customized
and
tightly
coupled
Red
Storm
supercompter.

Thunderbird
consists
of
4,096
Dell
PowerEdge
1850
servers,
each
equipped
with
two
Intel
64-bit
(EM64T)
processors,
for
a
total
of
more
than
8,000
processors.

A
high-performance
Infiniband
interconnect
from
Cisco
was
chosen
because
it
scales
more
linearly
than
most
proprietary
technologies
for
building
large
clusters
—
an
important
consideration
in
assembling
a
large
number
of
processors.
Lower
cost
was
another
factor
in
Sandia’s
selection
of
this
widely
used
interconnect.

The
procurement
also
includes
a
smaller
128-node
developmental
cluster
to
be
installed
in
the
Distributed
Information
Systems
Lab
at
Sandia’s
California
site.
It
will
enable
Sandia
to
develop
and
test
system
software
solutions
required
to
successfully
integrate
and
deploy
Thunderbird
for
production
use.

“Thunderbird
makes
important
strategic
connections
between
Sandia,
Dell,
and
other
vendors,”
says
Bill
Camp,
director
of
Sandia’s
Computation,
Computers,
Information
and
Mathematics
Center.
“Our
purchase
opens
a
venue
to
them
in
high-performance
cluster
computing.
Together
we
will
break
new
ground
by
deploying
a
cluster
with
commodity
processors
and
an
lnfiniband
interconnect
at
the
scale
of
thousands
of
processors.”

“Sandia
has
been
a
leader
in
putting
Infiniband
on
the
high-performance
computing
map,”
Ken
Washington
says.
“It
is
only
natural
that
we
be
the
place
where
such
a
large
Infiniband
cluster
is
first
realized
for
meeting
an
institutional
computing
requirement.”

Both
the
Ethernet
Input/Output
and
the
command
and
control
of
the
Thunderbird
cluster
are
based
on
the
Force
10
E-Series
switch/routers.
The
Force
10
E1200,
which
supports
1,260
gigabit
Ethernet
ports,
offers
the
industry’s
leading
gigabit
and
10-gigabit
port
density
—
providing
the
scalable
performance
required
to
support
the
largest
cluster
computers
in
deployment.
--
Neal
Singer

Technical
Library
trio
makes
worldwide
change

In
October
2005,
libraries
all
over
the
world
will
view
a
revised
cataloging
tag
that
will
broaden
the
scope
for
cataloging
classified
or
restricted
documents.

The
newly
revised
583
action
tag
will
be
published
in
the
MARC
21
Bibliographic
Format,
October
2005
Edition.
What
the
librarians
who
receive
this
reference
tool
and
catalog
materials
according
to
MAchine
Readable
Cataloging
(MARC)
may
not
realize
is
that
three
Library
staff
members
from
Sandia’s
Technical
Library
persevered
to
create
this
change.

Teresa
Gilbert,
Jennifer
Miller,
and
Jessica
Shaffer-Gant
(all
9536)
are
the
influences
behind
the
changes
to
this
tag,
which
can
now
be
used
to
record
report
classification
changes
or
reviews.

Previously,
there
was
no
appropriate
MARC
tag
to
record
historical
classification
information.
With
the
new
modification
to
the
583
action
tag,
catalogers
will
be
able
to
maintain
records
of
these
restriction
changes,
downgrades,
upgrades,
reviews,
etc.;
the
authorization;
date;
and
other
pertinent
information.

In
October
2003,
during
sessions
to
discuss
cataloging
procedures
of
classified
reports,
conflicting
opinions
arose
about
how
to
record
historical
classification
actions.
Jennifer,
who
was
team
leader
of
the
Technical
Library’s
Cataloging
Operations,
decided
to
look
to
the
Library
of
Congress
(LC)
for
guidance.

LC
asked
for
Sandia’s
input,
and
Teresa,
Jennifer,
and
Jessica
wrote
a
proposal
to
create
a
new
MARC
tag.
They
submitted
the
proposal
in
spring
2004.
After
review,
LC
suggested
modification
to
an
existing
tag.
The
Technical
Library
trio
drafted
a
new
proposal
in
May
of
this
year.
They
gave
examples
of
potential
uses
for
the
revised
tag
for
special
libraries
as
well
as
traditional
libraries,
globally.

Within
two
weeks
the
Library
of
Congress
accepted
the
proposal.

“I’m
really
pleased
that
we
could
make
an
impact
by
teaming
with
the
Library
of
Congress,”
says
Jennifer.

The
Technical
Library
has
already
started
implementing
the
revised
tag
into
its
internal
procedures.

“We
resolved
an
issue
rather
than
having
to
work
around
it,”
says
Teresa.
“Hopefully
this
change
will
be
as
useful
to
other
libraries
as
it
will
be
for
us.”